Imperva 10-Q 4 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 31, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	IMPV
Entity Registrant Name	IMPERVA INC
Entity Central Index Key	1,364,962
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		32,839,633

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	[1]
CURRENT ASSETS:
Cash and cash equivalents	$ 110,017	$ 168,252
Short-term investments	149,014	96,555
Restricted cash	69	79
Accounts receivable, net of allowance of $1,432 and $ 1,438 as of September 30, 2016 and December 31, 2015, respectively	45,702	61,051
Inventory	775	815
Prepaid expenses and other current assets	7,374	7,965
Total current assets	312,951	334,717
Property and equipment, net	20,521	12,164
Goodwill	34,972	34,972
Acquired intangible assets, net	6,935	7,991
Severance pay fund	5,137	4,530
Restricted cash	1,665	1,665
Deferred tax assets	771	588
Other assets	1,244	1,042
TOTAL ASSETS	384,196	397,669
CURRENT LIABILITIES:
Accounts payable	4,559	6,870
Accrued compensation and benefits	21,023	20,259
Accrued and other current liabilities	6,438	14,283
Deferred revenue	90,449	79,132
Total current liabilities	122,469	120,544
Other liabilities	5,349	4,515
Deferred revenue	26,101	27,525
Accrued severance pay	5,806	4,884
TOTAL LIABILITIES	159,725	157,468
Commitments and Contingencies (Note 7)	0	0
STOCKHOLDERS' EQUITY:
Preferred stock, $0.0001 par value - 5,000,000 shares authorized, no shares issued and outstanding as of September 30, 2016 and December 31, 2015, respectively	0	0
Common stock, $0.0001 par value - 145,000,000 shares authorized, 32,833,666 and 31,837,144 shares issued and outstanding as of September 30, 2016 and December 31, 2015, respectively	3	3
Additional paid-in capital	492,238	448,069
Accumulated deficit	(267,001)	(206,540)
Accumulated other comprehensive loss	(769)	(1,331)
TOTAL STOCKHOLDERS' EQUITY	224,471	240,201
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 384,196	$ 397,669
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,432	$ 1,438
Preferred stock, par value, per share	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value, per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	145,000,000	145,000,000
Common stock, shares issued	32,833,666	31,837,144
Common stock, shares outstanding	32,833,666	31,837,144

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net revenue:
Products and license	$ 22,486	$ 30,451	$ 58,157	$ 71,450
Services	45,921	32,898	127,896	90,134
Total net revenue	68,407	63,349	186,053	161,584
Cost of revenue:
Products and license	2,394	2,741	6,392	7,535
Services	11,354	9,148	32,841	26,250
Total cost of revenue	13,748	11,889	39,233	33,785
Gross profit	54,659	51,460	146,820	127,799
Operating expenses:
Research and development	15,289	13,183	46,884	38,973
Sales and marketing	38,128	31,806	119,845	97,130
General and administrative	12,669	11,401	38,800	32,781
Amortization of acquired intangible assets	352	352	1,056	1,056
Total operating expenses	66,438	56,742	206,585	169,940
Loss from operations	(11,779)	(5,282)	(59,765)	(42,141)
Other income (expense), net	107	91	(51)	(213)
Loss before provision for income taxes	(11,672)	(5,191)	(59,816)	(42,354)
Provision for income taxes	66	556	645	747
Net loss	$ (11,738)	$ (5,747)	$ (60,461)	$ (43,101)
Net loss per share of common stock stockholders, basic and diluted	$ (0.36)	$ (0.19)	$ (1.88)	$ (1.47)
Shares used in computing net loss per share of common stock, basic and diluted	32,445	30,797	32,130	29,362

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (11,738)	$ (5,747)	$ (60,461)	$ (43,101)
Other comprehensive gain (loss) (net of tax):
Net change in net unrealized gain (loss) on investments	(130)	8	76	(54)
Net change in unrealized gain (loss) on hedging instruments	224	(152)	486	425
Other comprehensive income (loss)	94	(144)	562	371
Comprehensive loss	$ (11,644)	$ (5,891)	$ (59,899)	$ (42,730)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total		Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2014	$ 97,243		$ 2	$ 256,388	$ (157,658)	$ (1,489)
Beginning balance, shares at Dec. 31, 2014			26,895,480
Proceeds from follow-on public offering, net of offering costs	127,854		$ 1	127,853
Proceeds from follow-on public offering, net of offering costs, shares			3,450,000
Issuance of common stock under employee equity plans, net of repurchases	12,652			12,652
Issuance of common stock under employee equity plans, net of repurchases, shares			1,074,862
Vesting of restricted stock	767			767
Stock-based compensation	38,801			38,801
Income tax (deficiencies) benefit from employee stock option exercises	60			60
Shares withheld for tax withholding on vesting of restricted stock units	(7,221)			(7,221)
Components of other comprehensive income (loss), net of tax
Change in unrealized gain (loss) on investments	(54)					(54)
Change in unrealized loss on hedging instruments	425					425
Net loss	(43,101)				(43,101)
Comprehensive loss	(42,730)
Ending balance at Sep. 30, 2015	227,426		$ 3	429,300	(200,759)	(1,118)
Ending balance, shares at Sep. 30, 2015			31,420,342
Beginning balance at Jun. 30, 2015						(974)
Components of other comprehensive income (loss), net of tax
Change in unrealized gain (loss) on investments	8
Change in unrealized loss on hedging instruments	(152)
Net loss	(5,747)
Comprehensive loss	(5,891)
Ending balance at Sep. 30, 2015	227,426		$ 3	429,300	(200,759)	(1,118)
Ending balance, shares at Sep. 30, 2015			31,420,342
Beginning balance at Dec. 31, 2015	240,201	[1]	$ 3	448,069	(206,540)	(1,331)
Beginning balance, shares at Dec. 31, 2015			31,837,144
Issuance of common stock under employee equity plans, net of repurchases	8,106			8,106
Issuance of common stock under employee equity plans, net of repurchases, shares			790,023
Issuance of holdback shares in connection with acquisitions, shares			206,499
Stock-based compensation	42,612			42,612
Income tax (deficiencies) benefit from employee stock option exercises	(29)			(29)
Shares withheld for tax withholding on vesting of restricted stock units	(6,520)			(6,520)
Components of other comprehensive income (loss), net of tax
Change in unrealized gain (loss) on investments	76					76
Change in unrealized loss on hedging instruments	486					486
Net loss	(60,461)				(60,461)
Comprehensive loss	(59,899)
Ending balance at Sep. 30, 2016	224,471		$ 3	492,238	(267,001)	(769)
Ending balance, shares at Sep. 30, 2016			32,833,666
Beginning balance at Jun. 30, 2016						(863)
Components of other comprehensive income (loss), net of tax
Change in unrealized gain (loss) on investments	(130)
Change in unrealized loss on hedging instruments	224
Net loss	(11,738)
Comprehensive loss	(11,644)
Ending balance at Sep. 30, 2016	$ 224,471		$ 3	$ 492,238	$ (267,001)	$ (769)
Ending balance, shares at Sep. 30, 2016			32,833,666
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (60,461)		$ (43,101)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	5,107		3,337
Stock-based compensation	45,736		38,801
Amortization of acquired intangibles	1,056		1,056
Loss on disposals	267		0
Amortization of premiums/accretion of discounts on short-term investments	144		398
Excess tax deficiencies (benefits) from share-based compensation	29		(60)
Other	(265)		0
Changes in operating assets and liabilities:
Accounts receivable, net	15,349		5,960
Inventory	40		(683)
Prepaid expenses and other assets	549		(1,760)
Accounts payable	(2,089)		(964)
Accrued compensation and benefits	(2,360)		571
Accrued and other liabilities	515		1,187
Severance pay (net)	315		356
Deferred revenue	9,893		10,116
Deferred tax assets	(183)		(26)
Net cash provided by operating activities	13,642		15,188
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales/maturities of short-term investments	54,916		20,721
Purchase of short-term investments	(107,403)		(75,399)
Net purchases of property and equipment	(13,953)		(4,038)
Change in restricted cash	10		(12)
Net cash used in investing activities	(66,430)		(58,728)
CASH FLOWS FROM FINANCING ACTIVITIES:
Settlement of holdback liability	(7,157)		0
Proceeds from follow-on public offering, net of offering costs	0		127,853
Offering costs relating to follow-on public offering	(112)		0
Proceeds from issuance of common stock, net of repurchases	8,106		12,668
Shares withheld for tax withholding on vesting of restricted stock units	(6,520)		(7,221)
Excess tax (deficiencies) benefits from share-based compensation	(29)		60
Net cash (used in) provided by financing activities	(5,712)		133,360
Effect of exchange rate changes on cash and cash equivalents	265		33
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(58,235)		89,853
CASH AND CASH EQUIVALENTS - Beginning of period	168,252	[1]	68,096
CASH AND CASH EQUIVALENTS - End of period	110,017		157,949
NONCASH INVESTING AND FINANCING ACTIVITIES:
Property and equipment incurred but not yet paid	295		132
Vesting of restricted and early exercised stock options	$ 0		$ 767
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	1. Basis of Presentation and Summary of Significant Accounting Policies Business Imperva, Inc. (together with its subsidiaries, the “Company”) was incorporated in April 2002 in Delaware. The Company is headquartered in Redwood Shores, California and has subsidiaries located throughout the world including Israel, Asia and Europe. The Company is engaged in the development, marketing, sales, service and support of cyber-security solutions that protect business-critical data and applications whether in the cloud or on premises. Basis of Presentation The Company has prepared the accompanying unaudited Condensed Consolidated Financial Statements in accordance with Article 10 of Regulation S-X and pursuant to the rules and regulations for Form 10-Q of the Securities and Exchange Commission (the “SEC”). Pursuant to those rules and regulations, the Company has condensed or omitted certain information and footnote disclosure it normally includes in its annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). In management’s opinion, the Company has made all adjustments (consisting only of normal, recurring adjustments, except as otherwise indicated) necessary to fairly present its consolidated financial position, results of operations, and cash flows. The Company’s interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. These financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, which was filed with the SEC on February 26, 2016 (the “Annual Report”). The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Concentration of Revenue and Accounts Receivable Significant customers are those which represent 10% or more of the Company’s total revenue or gross accounts receivable balance at each respective balance sheet date. For the three and nine months ended September 30, 2016, the Company had one customer that represented 13% and 13% of the Company’s total revenue respectively and the same customer represented 15% and 21% of accounts receivable as of September 30, 2016 and December 31, 2015 respectively. For the three and nine months ended September 30, 2015, the Company had one customer that represented 19% and 18% of the Company’s total revenue, respectively. Significant Accounting Policies There have been no material changes to the Company’s significant accounting policies as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. Recent Accounting Pronouncements In August 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The new standard will make eight targeted changes to how cash receipts and cash payments are presented and classified in the statement of cash flows. The standard will be effective for the Company beginning January 1, 2018, with early application permitted. The standard will require adoption on a retrospective basis unless it is impracticable to apply, in which case we would be required to apply the amendments prospectively as of the earliest date practicable. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements. In June 2016, the FASB Issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The new standard requires financial assets measured at amortized cost be presented at the net amount expected to be collected, through an allowance for credit losses that is deducted from the amortized cost basis. The standard will be effective for the Company beginning January 1, 2020, with early application permitted. The Company is evaluating the impact of adopting this new accounting guidance on its consolidated financial statements. In March 2016, the FASB Issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The updated guidance changes how companies account for certain aspects of share-based payment awards to employees, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The standard will be effective for the Company beginning January 1, 2017, with early application permitted. The Company is evaluating the impact of adopting this new accounting guidance on its consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update No. 2016-02 regarding ASC Topic 842 "Leases." The amendments in this guidance require balance sheet recognition of lease assets and lease liabilities by lessees for leases classified as operating leases, with an optional policy election to not recognize lease assets and lease liabilities for leases with a term of 12 months or less. The amendments also require new disclosures, including qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. The standard will be effective for the Company beginning January 1, 2019. The amendments require a modified retrospective approach with optional practical expedients. The Company is evaluating the impact of adopting this new accounting guidance on its consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09—Revenue (Topic 606): Revenue from Contracts with Customers. ASU No. 2014-09 will replace most existing U.S. GAAP guidance on this topic. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. In July 2015, the FASB approved a one-year deferral of the effective date for the new revenue reporting standard for entities reporting under U.S. GAAP. In accordance with the deferral, this guidance will be effective for the Company beginning January 1, 2018 and can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. Early adoption is permitted beginning January 1, 2017. The Company is evaluating the impact of adopting this new accounting standard on its consolidated financial statements and has not selected a transition method.

Cash, Cash Equivalents, and Sho

Cash, Cash Equivalents, and Short-Term Investments	9 Months Ended
	Sep. 30, 2016
Cash And Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Short-Term Investments	2. Cash, Cash Equivalents, and Short-Term Investments The Company considers all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Cash and cash equivalents consist of cash on hand, highly liquid investments in commercial paper, money market funds and various deposit accounts. The Company considers all high quality investments purchased with original maturities at the date of purchase greater than three months to be short-term investments. Investments are available to be used for current operations and are, therefore, classified as current assets even though maturities may extend beyond one year. Cash equivalents and short-term investments are classified as available-for-sale and are, therefore, recorded at fair value on the condensed consolidated balance sheets, with any unrealized gains and losses reported in accumulated other comprehensive income (loss), which is reflected as a separate component of stockholders’ equity in its condensed consolidated balance sheets, until realized. The Company uses the specific-identification method to compute gains and losses on the investments. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included as a component of other income (expense), net in the condensed consolidated statements of operations. Cash, cash equivalents and short-term investments consist of the following (in thousands): As of September 30, 2016 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash and cash equivalents: Cash $ 61,609 $ — $ — $ 61,609 Commercial paper 10,246 — 2 10,244 Money market funds 38,164 — — 38,164 Total $ 110,019 $ — $ 2 $ 110,017 Short-term investments: Commercial paper $ 19,200 $ — $ 16 $ 19,184 Corporate debt obligations 100,628 8 176 100,460 US government agencies 19,002 8 7 19,003 Bank deposits 10,367 — — 10,367 Total $ 149,197 $ 16 $ 199 $ 149,014 As of December 31, 2015 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash and cash equivalents: Cash $ 57,906 $ — $ — $ 57,906 Bank deposits 10,253 — — 10,253 Commercial paper 13,896 — 3 13,893 Money market funds 86,200 — — 86,200 Total $ 168,255 $ — $ 3 $ 168,252 Short-term investments: Corporate debt obligations $ 86,590 $ 2 $ 300 $ 86,292 Bank deposits 10,263 — — 10,263 Total $ 96,853 $ 2 $ 300 $ 96,555 The following table summarizes the cost and estimated fair value of short-term investments based on stated effective maturities as of September 30, 2016 (in thousands): As of September 30, 2016 Estimated Amortized Fair Cost Value Short-term investments: Due within one year $ 83,416 $ 83,357 Due within two years 65,781 65,657 Total $ 149,197 $ 149,014 The gross unrealized loss related to these securities was due primarily to changes in interest rates. The Company reviews its short-term investments on a regular basis to evaluate whether or not any security has experienced an other-than-temporary decline in fair value. The Company considers factors such as the length of time and extent to which the market value has been less than the cost, the financial condition and near-term prospects of the issuer and its intent to sell, or whether it is more likely than not the Company will be required to sell, the investment before recovery of the investment’s amortized cost basis. If the Company believes that an other-than-temporary decline exists in one of these securities, the Company writes down these investments to fair value. For debt securities, the portion of the write-down related to credit loss would be recorded to other income (expense), net, in the Company’s condensed consolidated statements of operations. Any portion not related to credit loss would be recorded to accumulated other comprehensive income (loss), which is reflected as a separate component of stockholders’ equity in the Company’s condensed consolidated balance sheets. During the nine months ended September 30, 2016 and 2015, the Company did not consider any of its investments to be other-than-temporarily impaired. The following tables show the short-term investments in an unrealized loss position and the related gross unrealized losses and fair value and length of time that the short-term investments have been in a continuous unrealized loss position (in thousands): As of September 30, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Commercial paper $ 19,184 $ 16 $ — $ — $ 19,184 $ 16 Corporate debt obligations 51,523 137 38,676 39 90,199 $ 176 US government agencies 9,998 7 - - 9,998 7 $ 80,705 $ 160 $ 38,676 $ 39 $ 119,381 $ 199 As of December 31, 2015 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt obligations $ 73,673 $ 286 $ 10,609 $ 14 $ 84,282 $ 300 $ 73,673 $ 286 $ 10,609 $ 14 $ 84,282 $ 300

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	3. Fair Value of Financial Instruments The Company evaluates assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level to classify them for each reporting period. There have been no transfers between fair value measurement levels during the nine months ended September 30, 2016. The Company’s cash equivalents and short-term investment instruments are classified within Level 1 or Level 2 of the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. The types of instruments valued based on quoted market prices in active markets include mutual funds and money market securities, and are generally classified within Level 1 of the fair value hierarchy. The types of instruments valued based on quoted prices in less active markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability include U.S. agency securities, investment-grade corporate bonds, bank deposits, and commercial paper. Such instruments are generally classified within Level 2 of the fair value hierarchy. The Company executes its foreign currency contracts primarily in the retail market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large multi-national and regional banks. The Company’s foreign currency contracts valuation inputs are based on quoted prices and quoted pricing intervals from public data sources and do not involve management judgment. These contracts are typically classified within Level 2 of the fair value hierarchy. The following table sets forth the Company’s assets and liabilities that were measured at fair value as of September 30, 2016 and December 31, 2015, by level within the fair value hierarchy (in thousands): As of September 30, 2016 Level I Level II Level III Fair Financial Assets: Cash equivalents: Commercial paper $ — $ 10,244 $ — $ 10,244 Money market funds 38,164 — — 38,164 Short-term investments: Commercial paper and debt obligations — 19,184 — 19,184 Corporate debt obligations — 100,460 — 100,460 US government agencies — 19,003 — 19,003 Bank deposits — 10,367 — 10,367 Prepaid expenses and other current assets - Forward foreign exchange contracts — 160 — 160 Total financial assets $ 38,164 $ 159,418 $ — $ 197,582 As of December 31, 2015 Level I Level II Level III Fair Value Financial Assets: Cash equivalents: Bank deposits $ — $ 10,253 $ — $ 10,253 Commercial paper — 13,893 — 13,893 Money market funds 86,200 — — 86,200 Short-term investments: Corporate debt obligations — 86,292 — 86,292 Bank deposits — 10,263 — 10,263 Total financial assets $ 86,200 $ 120,701 $ - $ 206,901 Financial Liability: Accrued and other current liabilities - Forward foreign exchange contracts $ — $ 595 $ — $ 595 In addition to the amounts disclosed in the above table, the fair value of the Company’s Israeli severance pay assets, which were comprised of Level II assets, was $5.1 million and $4.5 million as of September 30, 2016 and December 31, 2015, respectively.

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments	4. Derivative Instruments The Company’s primary objective for holding derivative instruments is to reduce its exposure to foreign currency rate changes. The Company reduces its exposure by entering into forward foreign exchange contracts with respect to operating expenses that are forecast to be incurred in currencies other than U.S. dollars. Substantially all of the Company’s revenue and capital purchasing activities and a majority of its operating expenditures are transacted in U.S. dollars. However, certain operating expenditures are incurred in or exposed to other currencies, primarily the Israeli shekel and the Euro. The Company has established forecasted transaction currency risk management programs to protect against fluctuations in fair value and the volatility of future cash flows caused by changes in exchange rates. The Company’s currency risk management program includes forward foreign exchange contracts designated as cash flow hedges. These forward foreign exchange contracts generally mature within 12 months. The Company does not enter into derivative financial instruments for trading purposes. Derivative instruments measured at fair value and their classification on the condensed consolidated balance sheets are presented in the following tables (in thousands): As of September 30, 2016 As of December 31, 2015 Notional Amount Fair Value Notional Amount Fair Value Foreign exchange forward contract derivatives in cash flow hedging relationships - included in prepaid expenses and other current assets (accrued and other current liabilities) $ 9,037 $ 160 $ 47,231 $ (595 ) Gains (losses) on derivative instruments and their classification on the condensed consolidated statement of operations are presented in the following table (in thousands): For the three months ended September 30 For the nine months ended September 30 2016 2015 2016 2015 Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships: Gains recognized in OCI (a) $ 458 $ — $ 1,774 $ 780 Losses recognized in OCI (a) $ — $ (312 ) $ (1,005 ) $ (762 ) Gains recognized from accumulated OCI into net loss (b) $ 108 $ — $ 257 $ — Losses recognized from accumulated OCI into net loss (b) $ (2 ) $ (113 ) $ (243 ) $ (684 ) (a) Net change in the fair value of the effective portion classified in other comprehensive income (loss) (“OCI”). (b) Effective portion of cash flow hedges reclassified from accumulated other comprehensive income (loss) into net loss, of which $18 and $88 were recognized within cost of sales and operating expenses, respectively, for the three months ended September 30, 2016 and $11 and $3 were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2016; $(14) and $(99) were recognized within cost of sales and operating expenses, respectively, for the three months ended September 30, 2015 and $(73) and $(611) were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2015. All amounts are reflected within the respective condensed consolidated statement of operations.

Acquired Intangible Assets

Acquired Intangible Assets	9 Months Ended
	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Acquired Intangible Assets	5. Acquired Intangible Assets The Company amortizes intangible assets, which consist of purchased technologies that have estimated useful lives ranging from 7 to 10 years, using the straight-line method when the consumption pattern of the asset is not apparent. The Company reviews such assets for impairment whenever an impairment indicator exists and continually monitors events and changes in circumstances that could indicate carrying amounts of the intangible assets may not be recoverable. When such events or changes in circumstances occur, the Company assesses recoverability by determining whether the carrying value of such assets exceed the estimates of future undiscounted future cash flows expected to be generated by such assets. Should impairment exist, the impairment loss would be measured based on the excess carrying value of the asset over the asset’s estimated fair value. There was no impairment of intangible assets recorded for the nine months ended September 30, 2016 and 2015. The weighted average remaining useful life of the Company’s acquired technology intangible assets is 5.2 years as of September 30, 2016. Acquired technology intangible assets subject to amortization are presented as follows (in thousands): As of September 30, 2016 As of December Acquired Technology $ 10,668 $ 10,668 Less: accumulated amortization (3,733 ) (2,677 ) Total acquired technology, net $ 6,935 $ 7,991 Acquired intangible assets are amortized over their estimated useful lives of 7 to 10 years. As of September 30, 2016, the amortization expense in future periods is expected to be as follows (in thousands): Acquired Fiscal Year Technology 2016 (remaining 3 months) $ 352 2017 1,408 2018 1,408 2019 1,408 2020 1,408 Thereafter 951 Total expected amortization expense $ 6,935

Revolving Credit Facility

Revolving Credit Facility	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Revolving Credit Facility	6. Revolving Credit Facility In September 2010, the Company entered into a revolving credit facility with a financial institution. The credit facility agreement, as amended, provides for borrowing capacity up to $7.5 million. The credit facility expires on April 1, 2019. As of September 30, 2016 and December 31, 2015, there was no balance outstanding on the credit facility. The credit facility is secured by the assets of the Company, and contains a restrictive covenant that requires the Company to maintain a minimum cash and cash equivalents balance of $3.0 million. The terms of this agreement requires payment of an unused line fee of 0.25% per quarter of the unused portion, standby letter of credit fees of 1% per annum of the stated amount of each letter of credit and bears interest at LIBOR plus 2.75%. As of September 30, 2016, the Company was compliant with the covenant of the credit facility.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies (a) Operating Leases The Company rents its facilities under operating leases with lease periods expiring through 2021. Future minimum payments under these facility operating leases and minimum rentals to be received under non-cancellable subleases are as follows as of September 30, 2016 (in thousands): Operating Leases Estimated Sublease Income Year Ending December 31: 2016 (remaining 3 months) $ 1,912 $ 215 2017 7,648 393 2018 8,076 176 2019 4,598 — 2020 4,220 — Thereafter 106 — Total $ 26,560 $ 784 Rent expense for the Company’s operating leases is recognized on a straight-line basis over the lease term. Rent expense for the nine months ended September 30, 2016 and 2015 was $4.6 million and $3.3 million, respectively. In connection with leases of office space, the Company has received tenant improvement allowances from the lessor for certain improvements made to the leased properties. The Company has recorded the tenant improvement allowances as a leasehold improvement within property and equipment, net, and as deferred rent within other liabilities on the condensed consolidated balance sheets. The deferred rent liability is amortized to rent expense over the term of the lease on a straight-line basis. The leasehold improvements are being amortized to expense over the period from when the improvements were placed into service until the end of their useful life, which is the end of the lease term. For the three and nine months ending September 30, 2016, the Company received tenant improvement allowances of $0.1 million. For the three and nine months ending September 30, 2015, the Company did not receive any tenant improvement allowances. In addition, certain of the Company’s operating lease agreements for office space also include rent holidays and scheduled rent escalations during the initial lease term. The Company has recorded the rent holidays as a deferred rent within other liabilities on the condensed consolidated balance sheets. The Company recognizes the deferred rent liability and scheduled rent increase on a straight-line basis into rent expense over the lease term commencing on the date the Company takes possession of the lease space. As of September 30, 2016 and December 31, 2015 the Company has $1.7 million and $1.7 million, respectively, in restricted deposits to secure bank guarantees provided to its lessors. (b) Cancelable Lease Agreement The Company leases motor vehicles under cancelable operating lease agreements. The Company has an option to cancel the lease agreements, which may result in penalties in a maximum amount of $0.1 million as of September 30, 2016. Motor vehicle lease expenses for the nine months ended September 30, 2016 and 2015 were $2.1 million and $2.0 million, respectively. (c) Purchase Commitments As of September 30, 2016 and December 31, 2015, the Company had purchase commitments of $4.5 million and $5.8 million, respectively, to purchase inventory, trial units, and research and development equipment from its vendors. The purchase commitments result from the Company’s contractual obligation to order or build inventory in advance of anticipated sales. According to the Company’s agreements with its vendors, the Company committed to purchase inventory within six months from the date the inventory arrived at the vendor’s warehouse. (d) Litigation From time to time, the Company is subject to legal proceedings and claims in the ordinary course of business. On April 11, 2014, a purported shareholder class action lawsuit was filed in the United States District Court for the Northern District of California against the Company and certain of its current and former officers. On August 7, 2014, the Court entered an order appointing lead plaintiff and counsel for the purported class. The lead plaintiff filed an amended complaint on October 10, 2014. The lawsuit named the Company and certain of its current and former officers and purported to bring suit on behalf of those investors who purchased the Company’s publicly traded securities between May 2, 2013 and April 9, 2014. The plaintiff alleged that defendants made false and misleading statements about the Company’s operations and business and financial results and purported to assert claims for violations of the federal securities laws. The amended complaint sought unspecified compensatory damages, interest thereon, costs incurred in the action and equitable/injunctive or other relief. On January 6, 2015, defendants filed a motion to dismiss the amended complaint. On September 17, 2015, the Court granted defendants’ motion to dismiss with leave to amend. The lead plaintiff filed an amended complaint on January 13, 2016, again naming the same current and former officers, alleging false and misleading statements about the Company’s operations and business and financial results, and seeking the same relief. On February 10, 2016, defendants filed a motion to dismiss the amended complaint. On May 16, 2016, the Court granted the motion in part and denied the motion in part. On September 7, 2016, defendants filed their operative answer to the amended complaint. In addition, the Company receives, and may in the future continue to receive, claims from third parties asserting, among other things, infringement of their intellectual property rights. Future litigation may be necessary to defend the Company, the Company’s channel partners and the Company’s customers by determining the scope, enforceability and validity of third-party proprietary rights or to establish our proprietary rights. In the opinion of management, liabilities associated with these claims, while possible, are not probable at this time, and therefore the Company has not recorded any accrual for them as of September 30, 2016 and December 31, 2015. Further, any possible range of loss cannot be reasonably estimated at this time. The ultimate outcome of any litigation is uncertain and, regardless of outcome, litigation can have an adverse impact on the Company because of defense costs, potential negative publicity, diversion of management resources and other factors. Accordingly, there can be no assurance that existing or future legal proceedings arising in the ordinary course of business or otherwise will not have a material adverse effect on the Company’s business, consolidated financial position, results of operations or cash flows. (e) Indemnification Under the indemnification provisions of its standard sales contracts, the Company agrees to defend its channel partners and end customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments and settlements entered on such claims. The Company’s exposure under these indemnifications provisions is generally limited to the total amount paid under the agreement. However, certain agreements included indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. To date, there have been no claims under such indemnification provisions. Accordingly, the Company has not recorded a liability on its condensed consolidated balance sheets for these indemnification provisions. In addition to the foregoing, the Company maintains director and officer insurance, which may cover certain liabilities arising from its obligation to indemnify its directors and officers. (f) Key Employee Settlement In June 2016, the Company offered to settle a compensation-related claim with a key employee that arose when the Company completed the acquisition of the company where the key employee was employed in March 2014. The Company ultimately resolved the matter in August 2016 for $3.4 million.

Stock Plans

Stock Plans	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Plans	8. Stock Plans (a) 2003 Stock Plan During 2003, the Board of Directors adopted the 2003 Stock Plan (the “2003 Plan”), which allowed for the grant of both incentive stock options and non-qualified stock options and the direct award or sale of shares of the Company’s common stock (including restricted common stock) to officers, employees, directors, consultants and other key persons. In connection with the Company’s initial public offering, which was completed in November 2011, the Board of Directors determined not to grant any further awards under the 2003 Plan upon completion of the public offering. The 2011 Stock Option and Incentive Plan (the “2011 Plan”) replaced the 2003 Plan in November 2011. Under the 2003 Plan, incentive stock options could have been granted to employees with exercise prices of no less than the fair value of the common stock on the grant date, and non-qualified options could have been granted to employees, directors, or consultants at exercise prices of no less than 85% of the fair value of the common stock on the grant date, as determined by the Board of Directors. If, at the time the Company granted an option, the optionee directly or by attribution owned stock possessing more than 10% of the total combined voting power of all classes of stock of the Company, the option price had to have been at least 110% of the fair value. Options granted under the 2003 Plan generally expire no later than ten years from the date of grant and, in general, vest four years from the date of grant. (b) 2011 Stock Option and Incentive Plan In September 2011, the Board of Directors adopted the 2011 Stock Option and Incentive Plan (the “2011 Plan”) which was subsequently approved by the Company’s stockholders. The 2011 Plan replaced the 2003 Plan and the Company no longer grants awards under the 2003 Plan. The Company initially reserved a total of 1,000,000 shares of common stock for issuance under the 2011 Plan. In addition, 955,568 reserved but unissued shares under the 2003 Stock Plan were added to the number of shares reserved for issuance under the 2011 Plan. The 2011 Plan also provided that the number of shares reserved and available for issuance under the plan would automatically increase each January 1, beginning in 2012 and ending in 2015, by 4% of the outstanding number of shares of common stock on the immediately preceding December 31. The last automatic increase occurred on January 1, 2015. In May 2016, the Company’s stockholders approved of an increase to the share reserve under the 2011 Stock Plan and Incentive Plan by 1,300,000 shares. The 2011 Plan permits the granting of incentive stock options, non-qualified stock options, restricted stock units (RSUs), stock appreciation rights, restricted shares of common stock and performance share awards. The exercise price of stock options may not be less than 100% of the fair market value of the common stock on the date of grant. Options granted pursuant to the 2011 Plan generally expire no later than ten years from the date of grant. The Company also grants RSUs, which generally vest over either a four-year period with 25% vesting at the end of one year and the remainder vesting quarterly thereafter or they completely vest at the end of a three-year period. Additionally, the Company grants performance-based RSUs to its executives on an annual basis. (c) 2011 Employee Stock Purchase Plan In September 2011, the Board of Directors adopted the 2011 Employee Stock Purchase Plan (the “ESPP”) which was subsequently approved by the Company’s stockholders. The ESPP took effect on November 8, 2011, the effective date of the registration statement for the Company’s initial public offering. The ESPP permits eligible employees to acquire shares of the Company’s common stock by accumulating funds through periodic payroll deductions of up to 15% of base salary. Each offering period may run for no more than 24 months and consist of no more than five purchase periods. The purchase price for shares of the Company’s common stock purchased under the ESPP will be 85% of the lesser of the fair market value of the Company’s common stock on the first day of the offering period or the last trading day of the applicable purchase period within that offering period. The Company initially reserved a total of 500,000 shares of common stock for future issuance under the ESPP. The number of shares reserved for issuance under the ESPP increases automatically on January 1 of each of the first eight years commencing in 2012 by the number of shares equal to 1% of the Company’s total outstanding shares as of the immediately preceding December 31. The Board of Directors or compensation committee may reduce the amount of the increase in any particular year. No more than 20,000,000 shares of common stock may be issued under the ESPP and no other shares may be added to the ESPP without the approval of the Company’s stockholders. On January 1, 2016, the share reserve under the 2011 Employee Stock Purchase Plan was automatically increased by 318,371 shares. (d) Inducement Stock Option Plan and Agreement and Inducement Restricted Stock Unit Plan and Agreement In August 2014 and August 2015, the Compensation Committee of the Board of Directors adopted an Inducement Stock Option Plan and Agreement (the “Inducement Option Plan”) and an Inducement Restricted Stock Unit Plan and Agreement (the “Inducement RSU Plan”), in each case created as employment inducement awards. In accordance with the terms of the Inducement Option Plans, the Company issued options to purchase up to 290,000 shares of the Company’s common stock at an exercise price equal to the fair market value of a share of the Company’s common stock on the dates of grant of the options. The options, which have a ten-year term, vest at the rate of 25% of the shares on each of the first anniversary of the vesting commencement date with an additional 6.25% of the shares subject to the option vesting each quarter thereafter so long as the participant has not been terminated. In accordance with the terms of the Inducement RSU Plans, the Company issued RSUs representing a total of 290,000 shares of the Company’s common stock. The RSUs, which expire following settlement, vest at the rate of 25% of the shares on each of the first anniversary of the vesting commencement date with an additional 6.25% of the shares subject to the RSU vesting each quarter thereafter so long as the participant has not been terminated. (e) 2015 Equity Inducement Plan In October 2015, the Board of Directors adopted the 2015 Equity Inducement Plan, a non-stockholder approved plan that provides for the granting of stock options and RSUs as employment inducement awards and in connection with acquisitions, subject to compliance with applicable securities laws and stock exchange requirements for such plans. The Company has reserved 100,000 shares of common stock for issuance under the 2015 Equity Inducement Plan. No awards have been made under the 2015 Equity Inducement Plan and the entire reserve remains available for grant. Under the terms of the 2015 Equity Inducement Plan, the exercise price of stock options may not be less than 100% of the fair market value of common stock on the date of grant and generally expire no later than ten years from the date of grant. (f) Incapsula 2010 Share Incentive Plan In March 2010, Incapsula’s board of directors adopted the Incapsula 2010 Share Incentive Plan (the “Incapsula Plan”), pursuant to which Incapsula was able to grant to its employees and service providers options to purchase shares of its common stock, restricted shares, or RSUs. As of November 2013, the total number of shares of common stock that could have been granted under the Incapsula Plan was not to exceed 10,263,211 shares in the aggregate, subject to certain adjustments. In November 2013, the board of directors of Incapsula approved the grant of RSUs for 7,095,461 shares of Incapsula’s common stock (“Incapsula RSUs”). As part of the Incapsula acquisition, the Incapsula RSUs were assumed and replaced by performance-based RSUs for Company Common Stock to be issued to continuing employees of Incapsula. The Incapsula RSUs were earned upon Incapsula’s achievement of revenue targets for Incapsula and Incapsula-related products and services for fiscal year 2014 and were converted into approximately 198,825 shares of Company Common Stock at the same exchange ratio applicable to the shares of Incapsula common stock acquired in the acquisition. In addition to performance conditions, the awards were dependent on the market price of Imperva’s common stock during February 2014, which was deemed a market condition under ASC 718. The outstanding options and RSUs under the Incapsula 2010 Stock Incentive Plan were assumed as part of the Incapsula acquisition and are equivalent to 247,184 shares of Company common stock on an as-converted basis. The Company does not intend to grant any additional shares under the Incapsula 2010 Stock Incentive Plan. Option Activity The following table summarizes option activity under the Plans and related information: Options Outstanding Weighted- Average Remaining Number of Shares Weighted Average Exercis e Contractual Term (in years) Aggregate Intrinsic Value (i n Balances - January 1, 2016 1,949,089 $ 39.27 8.09 $ 47,480 Granted 48,260 $ 53.59 Exercised (164,233 ) $ 29.72 Cancelled or forfeited (151,215 ) $ 46.46 Balances - September 30, 2016 1,681,901 $ 39.36 7.34 $ 25,899 Vested and expected to vest - September 30, 2016 1,539,544 $ 39.24 7.26 $ 24,647 Exercisable - September 30, 2016 888,151 $ 35.74 6.66 $ 16,756 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying awards and the closing stock price of $53.71 of the Company’s common stock on September 30, 2016. RSU Activity The following table summarizes RSU activity under the Plans and related information: Number of Restricted Stock Units Outstanding Weighted- Average Grant Date Fair Value Unvested - January 1, 2016 1,898,025 $ 49.53 Granted 929,168 $ 49.62 Granted, performance RSUs 273,900 $ 51.55 Released (681,176 ) $ 41.82 Cancelled or forfeited (244,068 ) $ 48.66 Unvested - September 30, 2016 2,175,849 $ 52.37 The aggregate intrinsic value of options exercised under the Plans was $2.1 million for the nine months ended September 30, 2016. The aggregate intrinsic value is calculated as the difference between the fair market value of the Company’s common stock on the date of the exercise and the exercise price of each option multiplied by the number of options exercised. As of September 30, 2016, total compensation cost related to unvested stock-based awards granted to employees under the Plans, but not yet recognized, was $87.0 million, net of estimated forfeitures. As of September 30, 2016, this cost will be amortized to expense over a weighted-average remaining period of 2.5 years, and will be adjusted for subsequent changes in estimated forfeitures. Future stock-based award grants will increase the amount of compensation expense to be recorded in these periods. There was no capitalized stock-based compensation expense during the nine months ended September 30, 2016 and 2015. Recognized stock-based compensation tax deficiencies (benefits) during the three and nine months ended September 30, 2016 was $15,000 and $29,000, respectively. The recognized stock-based compensation tax (benefits) during the three and nine months ended September 30, 2015 was ($17,000) and ($60,000) respectively. (g) Stock Compensation Expense The Company recognized stock-based compensation expense under the 2011 Stock Option and Incentive Plan, 2003 Stock Plan, Inducement Plans, 2011 Employee Stock Purchase Plan, and the Incapsula 2010 Share Incentive Plan in the condensed consolidated statements of operations as follows (in thousands): For the three months ended September 30 For the nine months ended September 30 2016 2015 2016 2015 Cost of revenue $ 1,079 $ 836 $ 3,604 $ 2,713 Research and development 3,380 3,311 11,431 10,122 Sales and marketing 4,405 3,314 17,182 12,824 General and administrative 4,113 4,201 13,519 13,142 Total stock-based compensation expense $ 12,977 $ 11,662 $ 45,736 $ 38,801 The Company did not issue stock option grants for the three months ended September 30, 2016. The fair value of stock option grants for the nine months ended September 30, 2016 and the three and nine months ended September 30, 2015 and ESPP grants for the nine months ended September 30, 2016 and 2015 was estimated using the following weighted average assumptions: For the three months ended September 30 For the nine months ended September 30 2016 2015 2016 2015 Stock option grants: Dividend rate - 0 % 0 % 0 % Risk-free interest rate - 1.7 % 1.4 % 1.7 % Expected term (in years) - 6.1 6.0 6.1 Expected volatility - 48 % 58 % 49 % ESPP grants: Dividend rate - - 0 % 0 % Risk-free interest rate - - 0.4 % 0.1 % Expected term (in years) - - 0.5 0.5 Expected volatility - - 58 % 64 % The fair value of the RSUs is determined using the closing price of the Company’s common stock on the date of the grant. Compensation is recognized on a straight-line basis over the requisite service period of each grant adjusted for estimated forfeitures. (h) Common Stock Subject to Repurchase In connection with the acquisition of Skyfence in the first quarter of 2014, the Company issued 532,262 shares of the Company’s common stock with a fair value per share of $59.08 which are subject to forfeiture based upon time-based vesting and continuing employment over the term of the corresponding four-year service period. 236,537 shares were fully vested as of September 30, 2016. (i) Follow-On Public Offering In March 2015, the Company completed a follow-on public offering whereby the Company sold 3,450,000 shares of common stock at a price of $39.00 per share, for aggregate net proceeds of $127.9 million, after deducting underwriting discounts, commissions and other offering costs of approximately $6.7 million.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Accumulated Other Comprehensive Loss	9. Accumulated Other Comprehensive Loss The changes in the balances of accumulated other comprehensive loss by component are as follows (in thousands): For the three months ended September 30, 2016 For the three months ended September 30, 2015 Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Balance at July 1 $ (759 ) $ (104 ) $ (863 ) $ (851 ) $ (123 ) $ (974 ) Other comprehensive income (loss) before reclassifications 330 (130 ) 200 (200 ) 8 (192 ) Amounts reclassified to net loss (106 ) — (106 ) 48 — 48 Change in other comprehensive income (loss) 224 (130 ) 94 (152 ) 8 (144 ) Balance at September 30 $ (535 ) $ (234 ) $ (769 ) $ (1,003 ) $ (115 ) $ (1,118 ) For the nine months ended September 30, 2016 For the nine months ended September 30, 2015 Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Balance at January 1 $ (1,021 ) $ (310 ) $ (1,331 ) $ (1,428 ) $ (61 ) $ (1,489 ) Other comprehensive income (loss) before reclassifications 500 76 576 11 (54 ) (43 ) Amounts reclassified to net loss (14 ) — (14 ) 414 — 414 Change in other comprehensive income (loss) 486 76 562 425 (54 ) 371 Balance at September 30 $ (535 ) $ (234 ) $ (769 ) $ (1,003 ) $ (115 ) $ (1,118 ) The following is a summary of reclassifications out of accumulated other comprehensive loss for the nine months ended September 30, 2016 and 2015 (in thousands): For the three months ended September 30, 2016 For the three months ended September 30, 2015 Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Unrealized gains (losses) on cash flow hedges: Current period unrealized gain (loss) $ 458 (128 ) $ 330 $ (312 ) (112 ) $ (200 ) Reclassification adjustments 1 (106 ) — (106 ) 113 65 48 Unrealized gains (losses) on cash flow hedges, net 352 (128 ) 224 (199 ) (47 ) (152 ) Unrealized gains (losses) on investments: Current period unrealized gain (loss) $ (201 ) 71 (130 ) $ 7 (1 ) 8 Unrealized gains (losses) on investments: (201 ) 71 (130 ) 7 (1 ) 8 Other comprehensive income (loss) $ 151 $ (57 ) $ 94 $ (192 ) $ (48 ) $ (144 ) For the nine months ended September 30, 2016 For the nine months ended September 30, 2015 Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Unrealized gains (losses) on cash flow hedges: Current period unrealized gain (loss) $ 769 (269 ) $ 500 $ 18 (7 ) $ 11 Reclassification adjustments 1 (14 ) — (14 ) 684 (270 ) 414 Unrealized gains (losses) on cash flow hedges, net 755 (269 ) 486 702 (277 ) 425 Unrealized gains (losses) on investments: Current period unrealized gain (loss) $ 116 (40 ) 76 $ (89 ) 35 (54 ) Unrealized gains (losses) on investments: 116 (40 ) 76 (89 ) 35 (54 ) Other comprehensive income (loss) $ 871 $ (309 ) $ 562 $ 613 $ (242 ) $ 371 1 Refer to note 4 for the affected line items in the condensed consolidated statement of operations.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The Company is subject to income tax in the United States as well as other tax jurisdictions in which it conducts business. Earnings from non-U.S. activities are subject to local country income tax. The Company does not provide for federal income taxes on the undistributed earnings of its foreign subsidiaries as such earnings are to be reinvested indefinitely. For the three months ended September 30, 2016 and 2015, the Company recorded income tax expense of $0.1 million and $0.6 million respectively. The Company recorded income tax expense of $0.6 million and $0.7 million for the nine months ended September 30, 2016 and 2015, respectively. The income tax expense for the three and nine months ended September 30, 2016, was primarily attributable to foreign and state income taxes, offset in part by an intraperiod tax benefit allocation related to unrealized gains reported in other comprehensive income. The income tax expense for the three and nine months ended September 30, 2015, was primarily attributable to foreign and state income taxes. Factors that impact the income tax provision include, but are not limited to, stock-based compensation expense, permanent tax adjustments, foreign operations and a valuation allowance against the Company’s domestic deferred tax assets.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Segment Information	11. Segment Information The Company operates its business in one operating segment, which is the development, marketing, sales, service and support of cyber-security solutions that protect business-critical data and applications whether in cloud or on premises. Operating segments are defined as components of an enterprise that engage in business activities for which separate financial information is available and evaluated by the chief operating decision maker in deciding how to allocate resources and assessing performance. The chief operating decision maker is the Company’s Chief Executive Officer. The Company’s net revenue by geographic region, based on the customer’s location, is summarized as follows (in thousands): For the three months ended September 30, For the nine months ended September 30, 2016 2015 2016 2015 Americas $ 39,995 $ 42,515 $ 107,069 $ 104,079 EMEA 18,542 14,113 49,859 38,604 APAC 9,870 6,721 29,125 18,901 Total net revenue $ 68,407 $ 63,349 $ 186,053 $ 161,584 The following table presents long-lived assets by location (in thousands): As of September 30, As of December 31, 2016 2015 United States $ 17,740 $ 9,913 Israel 9,692 10,224 Other 24 18 Total long-lived assets $ 27,456 $ 20,155

Net Loss per Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Net Loss per Share	12. Net Loss per Share Basic and diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding during the period. The computation of net loss per share for each period, including the number of weighted-average shares outstanding, is shown on the face of the condensed consolidated statements of operations. The following outstanding shares of common stock and potential common shares were excluded from the computation of diluted net loss per share of common stock for the periods presented because including them would have been antidilutive: For the three and nine months ended September 30, 2016 2015 Stock options to purchase common stock 1,681,901 2,216,426 Restricted stock units for common stock 2,175,849 2,128,749 Restricted stock issued in connection with Skyfence acquisition 270,565 355,499

Subsequent Event

Subsequent Event	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Event	13. Subsequent Event On October 31, 2016, the board of directors of the Company approved a restructuring plan to reduce sales, marketing and general and administrative expenses through reductions in headcount and spending generally. The Company anticipates incurring pre-tax restructuring charges of $10 million to $12 million in the fourth quarter of 2016. Substantially all of restructuring charges are termination-related costs, of which $7.0 million to $7.5 million would be for non-cash expenditures primarily consisting of stock-based compensation expense and $3.0 million to $4.5 million would be for cash severance costs. These actions are expected to be completed by the end of the fourth quarter of 2016.

Basis of Presentation and Sum21

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Business	Business Imperva, Inc. (together with its subsidiaries, the “Company”) was incorporated in April 2002 in Delaware. The Company is headquartered in Redwood Shores, California and has subsidiaries located throughout the world including Israel, Asia and Europe. The Company is engaged in the development, marketing, sales, service and support of cyber-security solutions that protect business-critical data and applications whether in the cloud or on premises.
Basis of Presentation	Basis of Presentation The Company has prepared the accompanying unaudited Condensed Consolidated Financial Statements in accordance with Article 10 of Regulation S-X and pursuant to the rules and regulations for Form 10-Q of the Securities and Exchange Commission (the “SEC”). Pursuant to those rules and regulations, the Company has condensed or omitted certain information and footnote disclosure it normally includes in its annual consolidated financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). In management’s opinion, the Company has made all adjustments (consisting only of normal, recurring adjustments, except as otherwise indicated) necessary to fairly present its consolidated financial position, results of operations, and cash flows. The Company’s interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. These financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015, which was filed with the SEC on February 26, 2016 (the “Annual Report”). The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Concentration of Revenue and Accounts Receivable	Concentration of Revenue and Accounts Receivable Significant customers are those which represent 10% or more of the Company’s total revenue or gross accounts receivable balance at each respective balance sheet date. For the three and nine months ended September 30, 2016, the Company had one customer that represented 13% and 13% of the Company’s total revenue respectively and the same customer represented 15% and 21% of accounts receivable as of September 30, 2016 and December 31, 2015 respectively. For the three and nine months ended September 30, 2015, the Company had one customer that represented 19% and 18% of the Company’s total revenue, respectively.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes to the Company’s significant accounting policies as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The new standard will make eight targeted changes to how cash receipts and cash payments are presented and classified in the statement of cash flows. The standard will be effective for the Company beginning January 1, 2018, with early application permitted. The standard will require adoption on a retrospective basis unless it is impracticable to apply, in which case we would be required to apply the amendments prospectively as of the earliest date practicable. We are evaluating the impact of adopting this new accounting guidance on our consolidated financial statements. In June 2016, the FASB Issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The new standard requires financial assets measured at amortized cost be presented at the net amount expected to be collected, through an allowance for credit losses that is deducted from the amortized cost basis. The standard will be effective for the Company beginning January 1, 2020, with early application permitted. The Company is evaluating the impact of adopting this new accounting guidance on its consolidated financial statements. In March 2016, the FASB Issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The updated guidance changes how companies account for certain aspects of share-based payment awards to employees, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. The standard will be effective for the Company beginning January 1, 2017, with early application permitted. The Company is evaluating the impact of adopting this new accounting guidance on its consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update No. 2016-02 regarding ASC Topic 842 "Leases." The amendments in this guidance require balance sheet recognition of lease assets and lease liabilities by lessees for leases classified as operating leases, with an optional policy election to not recognize lease assets and lease liabilities for leases with a term of 12 months or less. The amendments also require new disclosures, including qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. The standard will be effective for the Company beginning January 1, 2019. The amendments require a modified retrospective approach with optional practical expedients. The Company is evaluating the impact of adopting this new accounting guidance on its consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09—Revenue (Topic 606): Revenue from Contracts with Customers. ASU No. 2014-09 will replace most existing U.S. GAAP guidance on this topic. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. In July 2015, the FASB approved a one-year deferral of the effective date for the new revenue reporting standard for entities reporting under U.S. GAAP. In accordance with the deferral, this guidance will be effective for the Company beginning January 1, 2018 and can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. Early adoption is permitted beginning January 1, 2017. The Company is evaluating the impact of adopting this new accounting standard on its consolidated financial statements and has not selected a transition method.

Cash, Cash Equivalents, and S22

Cash, Cash Equivalents, and Short-Term Investments (Tables)	9 Months Ended
	Sep. 30, 2016
Cash And Cash Equivalents [Abstract]
Summary of Cash, Cash Equivalents and Short-Term Investments	Cash, cash equivalents and short-term investments consist of the following (in thousands): As of September 30, 2016 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash and cash equivalents: Cash $ 61,609 $ — $ — $ 61,609 Commercial paper 10,246 — 2 10,244 Money market funds 38,164 — — 38,164 Total $ 110,019 $ — $ 2 $ 110,017 Short-term investments: Commercial paper $ 19,200 $ — $ 16 $ 19,184 Corporate debt obligations 100,628 8 176 100,460 US government agencies 19,002 8 7 19,003 Bank deposits 10,367 — — 10,367 Total $ 149,197 $ 16 $ 199 $ 149,014 As of December 31, 2015 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Cash and cash equivalents: Cash $ 57,906 $ — $ — $ 57,906 Bank deposits 10,253 — — 10,253 Commercial paper 13,896 — 3 13,893 Money market funds 86,200 — — 86,200 Total $ 168,255 $ — $ 3 $ 168,252 Short-term investments: Corporate debt obligations $ 86,590 $ 2 $ 300 $ 86,292 Bank deposits 10,263 — — 10,263 Total $ 96,853 $ 2 $ 300 $ 96,555
Summary of Cost and Estimated Fair Value of Short-Term Investments	The following table summarizes the cost and estimated fair value of short-term investments based on stated effective maturities as of September 30, 2016 (in thousands): As of September 30, 2016 Estimated Amortized Fair Cost Value Short-term investments: Due within one year $ 83,416 $ 83,357 Due within two years 65,781 65,657 Total $ 149,197 $ 149,014
Schedule of Short-Term Investments at Fair Value and Length of Continuous Unrealized Loss Position	The following tables show the short-term investments in an unrealized loss position and the related gross unrealized losses and fair value and length of time that the short-term investments have been in a continuous unrealized loss position (in thousands): As of September 30, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Commercial paper $ 19,184 $ 16 $ — $ — $ 19,184 $ 16 Corporate debt obligations 51,523 137 38,676 39 90,199 $ 176 US government agencies 9,998 7 - - 9,998 7 $ 80,705 $ 160 $ 38,676 $ 39 $ 119,381 $ 199 As of December 31, 2015 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate debt obligations $ 73,673 $ 286 $ 10,609 $ 14 $ 84,282 $ 300 $ 73,673 $ 286 $ 10,609 $ 14 $ 84,282 $ 300

Fair Value of Financial Instr23

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Assets and Liabilities Subject to Fair Value Measurements on Recurring Basis	The following table sets forth the Company’s assets and liabilities that were measured at fair value as of September 30, 2016 and December 31, 2015, by level within the fair value hierarchy (in thousands): As of September 30, 2016 Level I Level II Level III Fair Financial Assets: Cash equivalents: Commercial paper $ — $ 10,244 $ — $ 10,244 Money market funds 38,164 — — 38,164 Short-term investments: Commercial paper and debt obligations — 19,184 — 19,184 Corporate debt obligations — 100,460 — 100,460 US government agencies — 19,003 — 19,003 Bank deposits — 10,367 — 10,367 Prepaid expenses and other current assets - Forward foreign exchange contracts — 160 — 160 Total financial assets $ 38,164 $ 159,418 $ — $ 197,582 As of December 31, 2015 Level I Level II Level III Fair Value Financial Assets: Cash equivalents: Bank deposits $ — $ 10,253 $ — $ 10,253 Commercial paper — 13,893 — 13,893 Money market funds 86,200 — — 86,200 Short-term investments: Corporate debt obligations — 86,292 — 86,292 Bank deposits — 10,263 — 10,263 Total financial assets $ 86,200 $ 120,701 $ - $ 206,901 Financial Liability: Accrued and other current liabilities - Forward foreign exchange contracts $ — $ 595 $ — $ 595

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments Measured at Fair Value and Classification on Condensed Consolidated Balance Sheets	Derivative instruments measured at fair value and their classification on the condensed consolidated balance sheets are presented in the following tables (in thousands): As of September 30, 2016 As of December 31, 2015 Notional Amount Fair Value Notional Amount Fair Value Foreign exchange forward contract derivatives in cash flow hedging relationships - included in prepaid expenses and other current assets (accrued and other current liabilities) $ 9,037 $ 160 $ 47,231 $ (595 )
Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations	Gains (losses) on derivative instruments and their classification on the condensed consolidated statement of operations are presented in the following table (in thousands): For the three months ended September 30 For the nine months ended September 30 2016 2015 2016 2015 Foreign Exchange Forward Contract Derivatives in cash flow hedging relationships: Gains recognized in OCI (a) $ 458 $ — $ 1,774 $ 780 Losses recognized in OCI (a) $ — $ (312 ) $ (1,005 ) $ (762 ) Gains recognized from accumulated OCI into net loss (b) $ 108 $ — $ 257 $ — Losses recognized from accumulated OCI into net loss (b) $ (2 ) $ (113 ) $ (243 ) $ (684 ) (a) Net change in the fair value of the effective portion classified in other comprehensive income (loss) (“OCI”). (b) Effective portion of cash flow hedges reclassified from accumulated other comprehensive income (loss) into net loss, of which $18 and $88 were recognized within cost of sales and operating expenses, respectively, for the three months ended September 30, 2016 and $11 and $3 were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2016; $(14) and $(99) were recognized within cost of sales and operating expenses, respectively, for the three months ended September 30, 2015 and $(73) and $(611) were recognized within cost of sales and operating expenses, respectively, for the nine months ended September 30, 2015. All amounts are reflected within the respective condensed consolidated statement of operations.

Acquired Intangible Assets (Tab

Acquired Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Acquired Technology Intangible Assets Subject to Amortization	Acquired technology intangible assets subject to amortization are presented as follows (in thousands): As of September 30, 2016 As of December Acquired Technology $ 10,668 $ 10,668 Less: accumulated amortization (3,733 ) (2,677 ) Total acquired technology, net $ 6,935 $ 7,991
Schedule of Expected Amortization Expense in Future Periods	Acquired intangible assets are amortized over their estimated useful lives of 7 to 10 years. As of September 30, 2016, the amortization expense in future periods is expected to be as follows (in thousands): Acquired Fiscal Year Technology 2016 (remaining 3 months) $ 352 2017 1,408 2018 1,408 2019 1,408 2020 1,408 Thereafter 951 Total expected amortization expense $ 6,935

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Payments Under Operating Leases	Future minimum payments under these facility operating leases and minimum rentals to be received under non-cancellable subleases are as follows as of September 30, 2016 (in thousands): Operating Leases Estimated Sublease Income Year Ending December 31: 2016 (remaining 3 months) $ 1,912 $ 215 2017 7,648 393 2018 8,076 176 2019 4,598 — 2020 4,220 — Thereafter 106 — Total $ 26,560 $ 784

Stock Plans (Tables)

Stock Plans (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Option Activity under Plans and Related Information	The following table summarizes option activity under the Plans and related information: Options Outstanding Weighted- Average Remaining Number of Shares Weighted Average Exercis e Contractual Term (in years) Aggregate Intrinsic Value (i n Balances - January 1, 2016 1,949,089 $ 39.27 8.09 $ 47,480 Granted 48,260 $ 53.59 Exercised (164,233 ) $ 29.72 Cancelled or forfeited (151,215 ) $ 46.46 Balances - September 30, 2016 1,681,901 $ 39.36 7.34 $ 25,899 Vested and expected to vest - September 30, 2016 1,539,544 $ 39.24 7.26 $ 24,647 Exercisable - September 30, 2016 888,151 $ 35.74 6.66 $ 16,756 (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying awards and the closing stock price of $53.71 of the Company’s common stock on September 30, 2016.
Summary of RSU Activity Outstanding and Weighted-Average Grant Date Fair Value	The following table summarizes RSU activity under the Plans and related information: Number of Restricted Stock Units Outstanding Weighted- Average Grant Date Fair Value Unvested - January 1, 2016 1,898,025 $ 49.53 Granted 929,168 $ 49.62 Granted, performance RSUs 273,900 $ 51.55 Released (681,176 ) $ 41.82 Cancelled or forfeited (244,068 ) $ 48.66 Unvested - September 30, 2016 2,175,849 $ 52.37
Stock-Based Compensation Expense	The Company recognized stock-based compensation expense under the 2011 Stock Option and Incentive Plan, 2003 Stock Plan, Inducement Plans, 2011 Employee Stock Purchase Plan, and the Incapsula 2010 Share Incentive Plan in the condensed consolidated statements of operations as follows (in thousands): For the three months ended September 30 For the nine months ended September 30 2016 2015 2016 2015 Cost of revenue $ 1,079 $ 836 $ 3,604 $ 2,713 Research and development 3,380 3,311 11,431 10,122 Sales and marketing 4,405 3,314 17,182 12,824 General and administrative 4,113 4,201 13,519 13,142 Total stock-based compensation expense $ 12,977 $ 11,662 $ 45,736 $ 38,801
Weighted Average Assumptions for Fair Value of Stock Options Grants and ESPP Grants	The Company did not issue stock option grants for the three months ended September 30, 2016. The fair value of stock option grants for the nine months ended September 30, 2016 and the three and nine months ended September 30, 2015 and ESPP grants for the nine months ended September 30, 2016 and 2015 was estimated using the following weighted average assumptions: For the three months ended September 30 For the nine months ended September 30 2016 2015 2016 2015 Stock option grants: Dividend rate - 0 % 0 % 0 % Risk-free interest rate - 1.7 % 1.4 % 1.7 % Expected term (in years) - 6.1 6.0 6.1 Expected volatility - 48 % 58 % 49 % ESPP grants: Dividend rate - - 0 % 0 % Risk-free interest rate - - 0.4 % 0.1 % Expected term (in years) - - 0.5 0.5 Expected volatility - - 58 % 64 %

Accumulated Other Comprehensi28

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Changes in Balances of Accumulated Other Comprehensive Loss	The changes in the balances of accumulated other comprehensive loss by component are as follows (in thousands): For the three months ended September 30, 2016 For the three months ended September 30, 2015 Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Balance at July 1 $ (759 ) $ (104 ) $ (863 ) $ (851 ) $ (123 ) $ (974 ) Other comprehensive income (loss) before reclassifications 330 (130 ) 200 (200 ) 8 (192 ) Amounts reclassified to net loss (106 ) — (106 ) 48 — 48 Change in other comprehensive income (loss) 224 (130 ) 94 (152 ) 8 (144 ) Balance at September 30 $ (535 ) $ (234 ) $ (769 ) $ (1,003 ) $ (115 ) $ (1,118 ) For the nine months ended September 30, 2016 For the nine months ended September 30, 2015 Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Unrealized gain (loss) on cash flow hedges Unrealized gain (loss) on investments Total Balance at January 1 $ (1,021 ) $ (310 ) $ (1,331 ) $ (1,428 ) $ (61 ) $ (1,489 ) Other comprehensive income (loss) before reclassifications 500 76 576 11 (54 ) (43 ) Amounts reclassified to net loss (14 ) — (14 ) 414 — 414 Change in other comprehensive income (loss) 486 76 562 425 (54 ) 371 Balance at September 30 $ (535 ) $ (234 ) $ (769 ) $ (1,003 ) $ (115 ) $ (1,118 )
Summary of Reclassifications Out of Accumulated Other Comprehensive Loss	The following is a summary of reclassifications out of accumulated other comprehensive loss for the nine months ended September 30, 2016 and 2015 (in thousands): For the three months ended September 30, 2016 For the three months ended September 30, 2015 Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Unrealized gains (losses) on cash flow hedges: Current period unrealized gain (loss) $ 458 (128 ) $ 330 $ (312 ) (112 ) $ (200 ) Reclassification adjustments 1 (106 ) — (106 ) 113 65 48 Unrealized gains (losses) on cash flow hedges, net 352 (128 ) 224 (199 ) (47 ) (152 ) Unrealized gains (losses) on investments: Current period unrealized gain (loss) $ (201 ) 71 (130 ) $ 7 (1 ) 8 Unrealized gains (losses) on investments: (201 ) 71 (130 ) 7 (1 ) 8 Other comprehensive income (loss) $ 151 $ (57 ) $ 94 $ (192 ) $ (48 ) $ (144 ) For the nine months ended September 30, 2016 For the nine months ended September 30, 2015 Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Pre-Tax Amount Tax Expense (Benefit) After-Tax Amount Unrealized gains (losses) on cash flow hedges: Current period unrealized gain (loss) $ 769 (269 ) $ 500 $ 18 (7 ) $ 11 Reclassification adjustments 1 (14 ) — (14 ) 684 (270 ) 414 Unrealized gains (losses) on cash flow hedges, net 755 (269 ) 486 702 (277 ) 425 Unrealized gains (losses) on investments: Current period unrealized gain (loss) $ 116 (40 ) 76 $ (89 ) 35 (54 ) Unrealized gains (losses) on investments: 116 (40 ) 76 (89 ) 35 (54 ) Other comprehensive income (loss) $ 871 $ (309 ) $ 562 $ 613 $ (242 ) $ 371 1 Refer to note 4 for the affected line items in the condensed consolidated statement of operations.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Company's Revenue by Geographic Region, Based on Customer's Location	The Company’s net revenue by geographic region, based on the customer’s location, is summarized as follows (in thousands): For the three months ended September 30, For the nine months ended September 30, 2016 2015 2016 2015 Americas $ 39,995 $ 42,515 $ 107,069 $ 104,079 EMEA 18,542 14,113 49,859 38,604 APAC 9,870 6,721 29,125 18,901 Total net revenue $ 68,407 $ 63,349 $ 186,053 $ 161,584
Long-Lived Assets by Location	The following table presents long-lived assets by location (in thousands): As of September 30, As of December 31, 2016 2015 United States $ 17,740 $ 9,913 Israel 9,692 10,224 Other 24 18 Total long-lived assets $ 27,456 $ 20,155

Net Loss per Share (Tables)

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share of Common Stock	The following outstanding shares of common stock and potential common shares were excluded from the computation of diluted net loss per share of common stock for the periods presented because including them would have been antidilutive: For the three and nine months ended September 30, 2016 2015 Stock options to purchase common stock 1,681,901 2,216,426 Restricted stock units for common stock 2,175,849 2,128,749 Restricted stock issued in connection with Skyfence acquisition 270,565 355,499

Basis of Presentation and Sum31

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - Customer	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Credit Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Number of customers representing 15% or more of accounts receivable	1		1
Number of customers representing 21% or more of accounts receivable					1
Revenue [Member] | Customer Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Minimum percentage of revenue or gross accounts receivable balance required to be significant customers	13.00%	19.00%	13.00%	18.00%
Number of customers representing 18% or more of revenue				1
Number of customers representing 19% or more of revenue		1
Accounts Receivable | Credit Concentration Risk [Member]
Revenue, Major Customer [Line Items]
Minimum percentage of revenue or gross accounts receivable balance required to be significant customers			15.00%		21.00%

Cash, Cash Equivalents, and S32

Cash, Cash Equivalents, and Short-Term Investments - Summary of Cash, Cash Equivalents and Short-Term Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Cash and cash equivalents, Amortized Cost	$ 110,019	$ 168,255
Cash and cash equivalents, Gross Unrealized Gains	0	0
Cash and cash equivalents, Gross Unrealized Losses	2	3
Cash and cash equivalents, Fair Value	110,017	168,252
Short-term investments, Amortized Cost	149,197	96,853
Short-term investments, Gross Unrealized Gains	16	2
Short-term investments, Gross Unrealized Losses	199	300
Short-term investments, Estimated Fair Value	149,014	96,555	[1]
Cash [Member]
Schedule of Investments [Line Items]
Cash and cash equivalents, Amortized Cost	61,609	57,906
Cash and cash equivalents, Gross Unrealized Gains	0	0
Cash and cash equivalents, Gross Unrealized Losses	0	0
Cash and cash equivalents, Fair Value	61,609	57,906
Bank Deposits [Member]
Schedule of Investments [Line Items]
Cash and cash equivalents, Amortized Cost		10,253
Cash and cash equivalents, Gross Unrealized Gains		0
Cash and cash equivalents, Gross Unrealized Losses		0
Cash and cash equivalents, Fair Value		10,253
Short-term investments, Amortized Cost	10,367	10,263
Short-term investments, Gross Unrealized Gains	0	0
Short-term investments, Gross Unrealized Losses	0	0
Short-term investments, Estimated Fair Value	10,367	10,263
Commercial Paper [Member]
Schedule of Investments [Line Items]
Cash and cash equivalents, Amortized Cost	10,246	13,896
Cash and cash equivalents, Gross Unrealized Gains	0	0
Cash and cash equivalents, Gross Unrealized Losses	2	3
Cash and cash equivalents, Fair Value	10,244	13,893
Short-term investments, Amortized Cost	19,200
Short-term investments, Gross Unrealized Gains	0
Short-term investments, Gross Unrealized Losses	16
Short-term investments, Estimated Fair Value	19,184
Money Market Funds [Member]
Schedule of Investments [Line Items]
Cash and cash equivalents, Amortized Cost	38,164	86,200
Cash and cash equivalents, Gross Unrealized Gains	0	0
Cash and cash equivalents, Gross Unrealized Losses	0	0
Cash and cash equivalents, Fair Value	38,164	86,200
Corporate Debt Obligations [Member]
Schedule of Investments [Line Items]
Short-term investments, Amortized Cost	100,628	86,590
Short-term investments, Gross Unrealized Gains	8	2
Short-term investments, Gross Unrealized Losses	176	300
Short-term investments, Estimated Fair Value	100,460	$ 86,292
US Government Agencies [Member]
Schedule of Investments [Line Items]
Short-term investments, Amortized Cost	19,002
Short-term investments, Gross Unrealized Gains	8
Short-term investments, Gross Unrealized Losses	7
Short-term investments, Estimated Fair Value	$ 19,003
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Cash, Cash Equivalents, and S33

Cash, Cash Equivalents, and Short-Term Investments - Summary of Cost and Estimated Fair Value of Short-Term Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Short Term Investments [Abstract]
Amortized Cost of short-term investments, Due within one year	$ 83,416
Amortized Cost of short-term investments, Due within two years	65,781
Short-term investments, Amortized Cost	149,197	$ 96,853
Estimated fair value of short-term investments, Due within one year	83,357
Estimated fair value of short-term investments, Due within two years	65,657
Short-term investments, Estimated Fair Value	$ 149,014	$ 96,555	[1]
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Cash, Cash Equivalents, and S34

Cash, Cash Equivalents, and Short-Term Investments - Schedule of Short-Term Investments at Fair Value and Length of Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 80,705	$ 73,673
Less than 12 Months, Unrealized Losses	160	286
12 Months or Greater, Fair Value	38,676	10,609
12 Months or Greater, Unrealized Losses	39	14
Total, Fair Value	119,381	84,282
Total, Unrealized Losses	199	300
Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	19,184
Less than 12 Months, Unrealized Losses	16
12 Months or Greater, Fair Value	0
12 Months or Greater, Unrealized Losses	0
Total, Fair Value	19,184
Total, Unrealized Losses	16
Corporate Debt Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	51,523	73,673
Less than 12 Months, Unrealized Losses	137	286
12 Months or Greater, Fair Value	38,676	10,609
12 Months or Greater, Unrealized Losses	39	14
Total, Fair Value	90,199	84,282
Total, Unrealized Losses	176	$ 300
US Government Agencies [Member]
Schedule Of Available For Sale Securities [Line Items]
Less than 12 Months, Fair Value	9,998
Less than 12 Months, Unrealized Losses	7
12 Months or Greater, Fair Value	0
12 Months or Greater, Unrealized Losses	0
Total, Fair Value	9,998
Total, Unrealized Losses	$ 7

Fair Value of Financial Instr35

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value transfers between level 1 to level 2	$ 0
Fair value transfers between level 2 to level 1	0
Fair value transfers into level 3	0
Fair value transfers out of level 3	0
Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Severance pay assets	$ 5,100,000	$ 4,500,000

Fair Value of Financial Instr36

Fair Value of Financial Instruments - Assets and Liabilities Subject to Fair Value Measurements on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 110,017	$ 168,252
Short-term investments	149,014	96,555	[1]
Commercial Paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	10,244	13,893
Short-term investments	19,184
Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	38,164	86,200
Corporate Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	100,460	86,292
US Government Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	19,003
Bank Deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		10,253
Short-term investments	10,367	10,263
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial assets	197,582	206,901
Fair Value, Measurements, Recurring [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial assets	38,164	86,200
Fair Value, Measurements, Recurring [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial assets	159,418	120,701
Fair Value, Measurements, Recurring [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial assets	0	0
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	10,244	13,893
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	10,244	13,893
Fair Value, Measurements, Recurring [Member] | Commercial Paper [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	38,164	86,200
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	38,164	86,200
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Commercial Paper And Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	19,184
Fair Value, Measurements, Recurring [Member] | Commercial Paper And Debt Obligations [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0
Fair Value, Measurements, Recurring [Member] | Commercial Paper And Debt Obligations [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	19,184
Fair Value, Measurements, Recurring [Member] | Commercial Paper And Debt Obligations [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0
Fair Value, Measurements, Recurring [Member] | Corporate Debt Obligations [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	100,460	86,292
Fair Value, Measurements, Recurring [Member] | Corporate Debt Obligations [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0	0
Fair Value, Measurements, Recurring [Member] | Corporate Debt Obligations [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	100,460	86,292
Fair Value, Measurements, Recurring [Member] | Corporate Debt Obligations [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0	0
Fair Value, Measurements, Recurring [Member] | US Government Agencies [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	19,003
Fair Value, Measurements, Recurring [Member] | US Government Agencies [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0
Fair Value, Measurements, Recurring [Member] | US Government Agencies [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	19,003
Fair Value, Measurements, Recurring [Member] | US Government Agencies [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	0
Fair Value, Measurements, Recurring [Member] | Bank Deposits [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		10,253
Short-term investments	10,367	10,263
Fair Value, Measurements, Recurring [Member] | Bank Deposits [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		0
Short-term investments	0	0
Fair Value, Measurements, Recurring [Member] | Bank Deposits [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		10,253
Short-term investments	10,367	10,263
Fair Value, Measurements, Recurring [Member] | Bank Deposits [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		0
Short-term investments	0	0
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaid Expenses and Other Current Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets - Forward foreign exchange contracts	160
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaid Expenses and Other Current Assets [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets - Forward foreign exchange contracts	0
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaid Expenses and Other Current Assets [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets - Forward foreign exchange contracts	160
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Prepaid Expenses and Other Current Assets [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets - Forward foreign exchange contracts	$ 0
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued and Other Current Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Accrued and other current liabilities - Forward foreign exchange contracts		595
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued and Other Current Liabilities [Member] | Level I [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Accrued and other current liabilities - Forward foreign exchange contracts		0
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued and Other Current Liabilities [Member] | Level II [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Accrued and other current liabilities - Forward foreign exchange contracts		595
Forward Foreign Exchange Contracts [Member] | Fair Value, Measurements, Recurring [Member] | Accrued and Other Current Liabilities [Member] | Level III [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Accrued and other current liabilities - Forward foreign exchange contracts		$ 0
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016
Forward Foreign Exchange Contracts [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Forward foreign exchange contracts maturity	12 months

Derivative Instruments - Deriva

Derivative Instruments - Derivative Instruments Measured at Fair Value and Classification on Condensed Consolidated Balance Sheets (Detail) - Forward Foreign Exchange Contracts [Member] - Designated As Hedging Instrument [Member] - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Notional Amount	$ 9,037,000
Derivative Fair Value	$ 160,000
Accrued and Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Notional Amount		$ 47,231,000
Derivative Fair Value		$ (595,000)

Derivative Instruments - Gains

Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations (Detail) - Designated As Hedging Instrument [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivatives, Fair Value [Line Items]
Gains recognized in OCI	$ 458	$ 0	$ 1,774	$ 780
Losses recognized in OCI		(312)	(1,005)	(762)
Gains recognized from accumulated OCI into net loss	108	0	257	0
Losses recognized from accumulated OCI into net loss	$ (2)	$ (113)	$ (243)	$ (684)

Derivative Instruments - Gain40

Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations (Parenthetical) (Detail) - Designated As Hedging Instrument [Member] - Unrealized Gain (Loss) on Cash Flow Hedges [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Cost of revenues [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge Gain (loss) reclassified	$ 18	$ (14)	$ 11	$ (73)
Operating Expenses [Member]
Derivatives, Fair Value [Line Items]
Cash flow hedge Gain (loss) reclassified	$ 88	$ (99)	$ 3	$ (611)

Acquired Intangible Assets - Ad

Acquired Intangible Assets - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 0	$ 0
Weighted average remaining useful life	5 years 2 months 12 days
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	7 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	10 years

Acquired Intangible Assets - Su

Acquired Intangible Assets - Summary of Acquired Technology Intangible Assets Subject to Amortization (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Intangible Assets Net Excluding Goodwill [Abstract]
Acquired Technology	$ 10,668	$ 10,668
Less: accumulated amortization	(3,733)	(2,677)
Total acquired technology, net	$ 6,935	$ 7,991	[1]
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Acquired Intangible Assets - Sc

Acquired Intangible Assets - Schedule of Expected Amortization Expense in Future Periods (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	[1]
Finite-Lived Intangible Assets [Line Items]
Total acquired technology, net	$ 6,935	$ 7,991
Purchased Technology [Member]
Finite-Lived Intangible Assets [Line Items]
2016 (remaining 3 months)	352
2,017	1,408
2,018	1,408
2,019	1,408
2,020	1,408
Thereafter	951
Total acquired technology, net	$ 6,935
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Revolving Credit Facility - Add

Revolving Credit Facility - Additional Information (Detail) - Revolving Credit Facility [Member] - London Interbank Offered Rate (LIBOR) [Member] - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 7,500,000
Credit facility expiration date	Apr. 1, 2019
Outstanding credit facility	$ 0	$ 0
Minimum cash and cash equivalents	$ 3,000,000
Percentage in payment of unused line fee	0.25%
Stand by letter of credit fees	1.00%
Interest rate spread	2.75%
Compliance of credit facility, description	The Company was compliant with the covenant of the credit facility.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Loss Contingencies [Line Items]
Operating lease expiration year				2,021
Rent expense				$ 4,600,000	$ 3,300,000
Tenant improvement allowances		$ 100,000	$ 0	100,000	0
Restricted cash		1,665,000		1,665,000		$ 1,665,000	[1]
Purchase commitments		4,500,000		$ 4,500,000		5,800,000
Period of purchase commitment of inventory from specified date				6 months
Loss contingency accrual		0		$ 0		$ 0
Cancelable Lease Agreement [Member]
Loss Contingencies [Line Items]
Motor vehicle lease expenses				2,100,000	$ 2,000,000
Key Employee Settlement [Member]
Loss Contingencies [Line Items]
Loss on settlement of claim	$ 3,400,000
Maximum [Member] | Cancelable Lease Agreement [Member]
Loss Contingencies [Line Items]
Penalties		$ 100,000		$ 100,000
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Commitments and Contingencies46

Commitments and Contingencies - Future Minimum Payments Under Operating Leases and Minimum Rentals to be Received Under Non-Cancellable Subleases (Detail) $ in Thousands	Sep. 30, 2016USD ($)
Operating Leases
2016 (remaining 3 months)	$ 1,912
2,017	7,648
2,018	8,076
2,019	4,598
2,020	4,220
Thereafter	106
Total	26,560
Estimated Sublease Income
2016 (remaining 3 months)	215
2,017	393
2,018	176
2,019	0
2,020	0
Thereafter	0
Total	$ 784

Stock Plans - Additional Inform

Stock Plans - Additional Information (Detail)

Jan. 01, 2016shares

May 31, 2016shares

Oct. 31, 2015shares

Aug. 31, 2014shares

Nov. 30, 2013shares

Jan. 31, 2012

Sep. 30, 2011Periodshares

Sep. 30, 2016USD ($)$ / sharesshares

Sep. 30, 2015USD ($)

Mar. 31, 2015USD ($)$ / sharesshares

Sep. 30, 2016USD ($)$ / sharesshares

Sep. 30, 2015USD ($)

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of stock option outstanding, granted

0

48,260

Performance-based restricted stock units granted

929,168

Capitalized stock-based compensation expense | $

$ 0

$ 0

Recognized stock-based compensation tax deficiencies (benefits) | $

$ 15,000

$ (17,000)

29,000

(60,000)

Aggregate net proceeds from sale of common stock, net of underwriting discounts, commissions and offering costs | $

8,106,000

12,668,000

Underwriting discounts, commissions and other offering expenses | $

$ 112,000

$ 0

Follow-On Public Offering [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Issuance of common stock, shares

3,450,000

Sale of common stock, price per share | $ / shares

$ 39

Aggregate net proceeds from sale of common stock, net of underwriting discounts, commissions and offering costs | $

$ 127,900,000

Underwriting discounts, commissions and other offering expenses | $

$ 6,700,000

Skyfence Networks Ltd. [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Nonvested awards, compensation cost not yet recognized, period for recognition

4 years

Business acquisition purchase price, shares issued

532,262

Closing price of stock | $ / shares

$ 59.08

$ 59.08

Common stock, shares vested

236,537

Restricted Stock Units for Common Stock [Member] | Incapsula [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares issuable, as-converted to common stock-basis

198,825

Outstanding Options and RSUs [Member] | Incapsula [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares issuable, as-converted to common stock-basis

247,184

2003 Stock Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Increase in reserve share

955,568

2003 Stock Plan [Member] | Stock options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum percentage of fair value of common stock on grant date

85.00%

2003 Stock Plan [Member] | Stock options [Member] | Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expiration period

10 years

2003 Stock Plan [Member] | Stock options [Member] | Minimum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

4 years

2003 Stock Plan [Member] | Greater 10% Ownership [Member] | Stock options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum percentage of fair value of common stock on grant date

110.00%

Minimum percentage of combined voting power

10.00%

2011 Stock Option and Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Reserve of common stock for future issuance

1,000,000

Increase in reserve share

1,300,000

Increase percentage of common stock outstanding

4.00%

2011 Stock Option and Incentive Plan [Member] | Stock options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum percentage of fair value of common stock on grant date

100.00%

Expiration period

10 years

2011 Stock Option and Incentive Plan [Member] | Restricted Stock Units for Common Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period

4 years

Description of vesting terms

The Company also grants RSUs, which generally vest over either a four-year period with 25% vesting at the end of one year and the remainder vesting quarterly thereafter or they completely vest at the end of a three-year period.

2011 Stock Option and Incentive Plan [Member] | Restricted Stock Units for Common Stock [Member] | Share-based Compensation Award, Tranche One [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting percentage at the end of period

25.00%

2011 Employee Stock Purchase Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Reserve of common stock for future issuance

500,000

Increase in reserve share

318,371

Increase percentage of common stock outstanding

1.00%

Program effective date

Nov. 8, 2011

Percentage in payroll of deduction base salary to acquire shares of common stock

15.00%

Offering period

24 months

Percentage of fair value of common stock on offering period

85.00%

Number of years, shares reserved for issuance increase

8 years

2011 Employee Stock Purchase Plan [Member] | Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Reserve of common stock for future issuance

20,000,000

Number of purchase periods for offering | Period

5

Inducement Stock Option Plan And Agreement [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Description of vesting terms

In accordance with the terms of the Inducement Option Plans, the Company issued options to purchase up to 290,000 shares of the Company’s common stock at an exercise price equal to the fair market value of a share of the Company’s common stock on the dates of grant of the options. The options, which have a ten-year term, vest at the rate of 25% of the shares on each of the first anniversary of the vesting commencement date with an additional 6.25% of the shares subject to the option vesting each quarter thereafter so long as the participant has not been terminated.

Number of stock option outstanding, granted

290,000

Inducement Stock Option Plan And Agreement [Member] | Share-based Compensation Award, Tranche One [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting percentage at the end of period

25.00%

Inducement Stock Option Plan And Agreement [Member] | Quarterly Vesting [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting percentage at the end of period

6.25%

Inducement Restricted Stock Unit Plan and Agreement [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Description of vesting terms

In accordance with the terms of the Inducement RSU Plans, the Company issued RSUs representing a total of 290,000 shares of the Company’s common stock. The RSUs, which expire following settlement, vest at the rate of 25% of the shares on each of the first anniversary of the vesting commencement date with an additional 6.25% of the shares subject to the RSU vesting each quarter thereafter so long as the participant has not been terminated.

Shares available for grant

290,000

Inducement Restricted Stock Unit Plan and Agreement [Member] | Share-based Compensation Award, Tranche One [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting percentage at the end of period

25.00%

Inducement Restricted Stock Unit Plan and Agreement [Member] | Quarterly Vesting [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting percentage at the end of period

6.25%

2015 Equity Inducement Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Reserve of common stock for future issuance

100,000

2015 Equity Inducement Plan [Member] | Stock options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum percentage of fair value of common stock on grant date

100.00%

Expiration period

10 years

Incapsula 2010 Share Incentive Plan [Member] | Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Reserve of common stock for future issuance

10,263,211

Incapsula 2010 Share Incentive Plan [Member] | Restricted Stock Units for Common Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Performance-based restricted stock units granted

7,095,461

2003 Stock and 2011 Imperva Stock Option and Incentive Plans [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Intrinsic value of options exercised | $

$ 2,100,000

Compensation cost related to unvested stock-based awards granted, but not yet recognized | $

$ 87,000,000

$ 87,000,000

Nonvested awards, compensation cost not yet recognized, period for recognition

2 years 6 months

Stock Plans - Summary of Option

Stock Plans - Summary of Option Activity under Plans and Related Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Stock Options Outstanding, Beginning balance		1,949,089
Number of Stock Options Outstanding, Granted	0	48,260
Number of Stock Options Outstanding, Exercised		(164,233)
Number of Stock Options Outstanding, Cancelled or forfeited		(151,215)
Number of Stock Options Outstanding, Ending balance	1,681,901	1,681,901	1,949,089
Number of Shares, Vested and expected to vest	1,539,544	1,539,544
Number of Shares, Exercisable	888,151	888,151
Weighted Average Exercise Price of Stock Options Outstanding	$ 39.36	$ 39.36	$ 39.27
Weighted Average Exercise Price, Granted		53.59
Weighted Average Exercise Price, Exercised		29.72
Weighted Average Exercise Price, Cancelled or forfeited		46.46
Weighted Average Exercise Price, Vested and expected to vest	39.24	39.24
Weighted Average Exercise Price, Exercisable	$ 35.74	$ 35.74
Weighted-Average Remaining Contractual Term (in years)		7 years 4 months 2 days	8 years 1 month 2 days
Weighted-Average Remaining Contractual Term (in years), Vested and expected to vest		7 years 3 months 4 days
Weighted-Average Remaining Contractual Term (in years), Exercisable		6 years 7 months 28 days
Aggregate Intrinsic Value	$ 25,899	$ 25,899	$ 47,480
Aggregate Intrinsic Value, Vested and expected to vest	24,647	24,647
Aggregate Intrinsic Value, Exercisable	$ 16,756	$ 16,756

Stock Plans - Summary of Opti49

Stock Plans - Summary of Option Activity under Plans and Related Information (Parenthetical) (Detail)	Sep. 30, 2016$ / shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Closing stock price	$ 53.71

Stock Plans - Summary of RSU Ac

Stock Plans - Summary of RSU Activity Outstanding and Weighted-Average Grant Date Fair Value (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Restricted Stock Units Outstanding, Unvested - Beginning Balance	1,898,025
Number of Restricted Stock Units Outstanding, Granted	929,168
Number of Restricted Stock Units Outstanding, Granted, performance RSUs	273,900
Number of Restricted Stock Units Outstanding, Released	(681,176)
Number of Restricted Stock Units Outstanding, Cancelled or forfeited	(244,068)
Number of Restricted Stock Units Outstanding, Unvested - Ending Balance	2,175,849
Weighted-Average Grant Date Fair Value, Unvested	$ 52.37	$ 49.53
Weighted-Average Grant Date Fair Value, Granted	49.62
Weighted-Average Grant Date Fair Value, Granted, performance RSUs	51.55
Weighted-Average Grant Date Fair Value, Released	41.82
Weighted-Average Grant Date Fair Value, Cancelled or forfeited	$ 48.66

Stock Plans - Stock-Based Compe

Stock Plans - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 12,977	$ 11,662	$ 45,736	$ 38,801
Cost of revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,079	836	3,604	2,713
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	3,380	3,311	11,431	10,122
Sales and Marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	4,405	3,314	17,182	12,824
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 4,113	$ 4,201	$ 13,519	$ 13,142

Stock Plans - Weighted Average

Stock Plans - Weighted Average Assumptions for Fair Value of Stock Options Grants and ESPP Grants (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend rate		0.00%	0.00%	0.00%
Risk-free interest rate		1.70%	1.40%	1.70%
Expected term (in years)	0 years	6 years 1 month 6 days	6 years	6 years 1 month 6 days
Expected volatility		48.00%	58.00%	49.00%
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend rate			0.00%	0.00%
Risk-free interest rate			0.40%	0.10%
Expected term (in years)	0 years	0 years	6 months	6 months
Expected volatility			58.00%	64.00%

Accumulated Other Comprehensi53

Accumulated Other Comprehensive Loss - Changes in Balances of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			$ 240,201	[1]	$ 97,243
Other comprehensive income (loss) before reclassifications	$ 200	$ (192)	576		(43)
Amounts reclassified to net loss	(106)	48	(14)		414
Other comprehensive income (loss)	94	(144)	562		371
Ending balance	224,471	227,426	224,471		227,426
Unrealized Gain (Loss) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(759)	(851)	(1,021)		(1,428)
Other comprehensive income (loss) before reclassifications	330	(200)	500		11
Amounts reclassified to net loss	(106)	48	(14)		414
Other comprehensive income (loss)	224	(152)	486		425
Ending balance	(535)	(1,003)	(535)		(1,003)
Unrealized Gain (Loss) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(104)	(123)	(310)		(61)
Other comprehensive income (loss) before reclassifications	(130)	8	76		(54)
Other comprehensive income (loss)	(130)	8	76		(54)
Ending balance	(234)	(115)	(234)		(115)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(863)	(974)	(1,331)		(1,489)
Ending balance	$ (769)	$ (1,118)	$ (769)		$ (1,118)
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.

Accumulated Other Comprehensi54

Accumulated Other Comprehensive Loss - Summary of Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), Pre-Tax Amount	$ 151	$ (192)	$ 871	$ 613
Other comprehensive income (loss), Tax Expense (Benefit)	(57)	(48)	(309)	(242)
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	200	(192)	576	(43)
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	(106)	48	(14)	414
Other comprehensive income (loss)	94	(144)	562	371
Unrealized Gains (Losses) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassification adjustments, Pre-Tax Amount	458	(312)	769	18
Other comprehensive income (loss), Reclassification adjustments, Pre-Tax Amount	(106)	113	(14)	684
Other comprehensive income (loss), Pre-Tax Amount	352	(199)	755	702
Other comprehensive income (loss) before reclassification adjustments, Tax Expense (Benefit)	(128)	(112)	(269)	(7)
Other comprehensive income (loss), Reclassification adjustments, Tax Expense (Benefit)		65		(270)
Other comprehensive income (loss), Tax Expense (Benefit)	(128)	(47)	(269)	(277)
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	330	(200)	500	11
Other comprehensive income (loss), Reclassification adjustments, After-Tax Amount	(106)	48	(14)	414
Other comprehensive income (loss)	224	(152)	486	425
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassification adjustments, Pre-Tax Amount	(201)	7	116	(89)
Other comprehensive income (loss), Pre-Tax Amount	(201)	7	116	(89)
Other comprehensive income (loss) before reclassification adjustments, Tax Expense (Benefit)	71	(1)	(40)	35
Other comprehensive income (loss), Tax Expense (Benefit)	71	(1)	(40)	35
Other comprehensive income (loss) before reclassification adjustments, After-Tax Amount	(130)	8	76	(54)
Other comprehensive income (loss)	$ (130)	$ 8	$ 76	$ (54)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 66	$ 556	$ 645	$ 747

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016Segment
Segment Reporting [Abstract]
Number of operating segments	1

Segment Information - Company's

Segment Information - Company's Revenue by Geographic Region, Based on Customer's Location (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue	$ 68,407	$ 63,349	$ 186,053	$ 161,584
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue	39,995	42,515	107,069	104,079
EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue	18,542	14,113	49,859	38,604
APAC [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net revenue	$ 9,870	$ 6,721	$ 29,125	$ 18,901

Segment Information - Long-Live

Segment Information - Long-Lived Assets by Location (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	$ 27,456	$ 20,155
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	17,740	9,913
Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	9,692	10,224
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total long-lived assets	$ 24	$ 18

Net Loss per Share - Antidiluti

Net Loss per Share - Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share of Common Stock (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	1,681,901	2,216,426	1,681,901	2,216,426
Restricted Stock Units for Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	2,175,849	2,128,749	2,175,849	2,128,749
Restricted Stock Issued In Connection with Skyfence Acquisition [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	270,565	355,499	270,565	355,499

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Dec. 31, 2016	Sep. 30, 2016
Subsequent Event [Line Items]
Restructuring plan approval date by board of directors		Oct. 31, 2016
Scenario, Forecast [Member] | Minimum [Member]
Subsequent Event [Line Items]
Expected pre-tax restructuring charges	$ 10
Termination-related costs, non-cash expenditures	7
Termination related costs, cash severance costs	3
Scenario, Forecast [Member] | Maximum [Member]
Subsequent Event [Line Items]
Expected pre-tax restructuring charges	12
Termination-related costs, non-cash expenditures	7.5
Termination related costs, cash severance costs	$ 4.5